The beneficial effects of Long-term Oxygen Therapy (LTOT) in the home for patients with Chronic Obstructive Pulmonary Disease (COPD), and other lung diseases causing hypoxemia, are well known. The number of patients with COPD is increasing in most countries, and in the U.S., it is now one of the leading causes of death. LTOT increases a patient's survival rate and also has the potential to improve considerably a patient's quality of life. Since LTOT must be given for as long as possible during the day, it is important to extend daily hours of oxygen therapy into the mobile period of the day. This can be achieved through the use of compact, lightweight, portable sources of oxygen gas. Thus, there exists a clear need for a new technology-based oxygen generator that satisfies all the requirements for LTOT both within and outside the home. Currently, providing ambulatory oxygen with LOX systems is problematic because of the cost of LOX and hence lower profit margins for suppliers. The aims of portable oxygen are to increase exercise tolerance, reduce exercise dyspnea, improve quality of life, and extend the daily hours of LTOT. In response to the identified need, this project is specifically aimed at improving the delivery of oxygen to ambulatory patients in the home and office setting using an innovative electrochemical life support system. The technology will have a dramatic improvement in clinical benefits, patient convenience and delivery costs. The portable electrochemical system will produce on demand a supply of humidified, but otherwise pure, oxygen gas, while having a system weight less than 10 Ib and system power requirements less than 600 Watts. The system will provide instantaneous start-up and it is estimated that the oxygen generator will cost less than $1,000. A dual-use development approach will be adopted because the portable electrochemical oxygen generator technology has both government and other commercial applications such as battlefield life support, forward medical treatment areas, casualty transport vehicles, "oxygen trickle charger" for commercial and military aircraft, and hyperbaric oxygen therapy for decompression sickness, air embolism, and carbon monoxide poisoning.